JP3793223B2 - Ink jet ink, ink jet recording method, ink cartridge, recording unit, and ink jet recording apparatus - Google Patents

Abstract

Provided is an ink jet ink containing a coloring material having a buffer region in an ink use range, the ink jet ink being capable of suppressing the occurrence of the deterioration (dissolution) of a heating portion surface in contact with liquid; and the disconnection of wiring for applying a voltage to a heating portion even when long term continuous printing is performed. The ink jet ink is used for an ink jet recording apparatus equipped with a recording head having a heating portion surface in contact with liquid comprising a metal and/or a metal oxide. The ink jet ink contains a coloring material in a content (mass%) of 3 mass% or more with respect to the total mass of the ink jet ink. The coloring material is a colorant having a buffer region in an ink use range, and comprises a compound represented by the following general formula (I) and/or a compound represented by the following general formula (II). General formula (II) €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒH(OCH 2 CH 2 ) p R 5

Description

  The present invention relates to an inkjet ink excellent in printing durability and the like, an inkjet recording method, an ink cartridge, a recording unit, and an inkjet recording apparatus.

  The ink jet recording method is a recording method in which ink droplets are applied on plain paper and a recording medium such as glossy media to form an image, and it is rapidly spreading due to its low price and improved recording speed. Progressing. Further, in addition to the progress of higher image quality of recorded images, with the rapid spread of digital cameras, it has become widely popular as a method for outputting photographic images comparable to silver salt photographs.

  In recent years, higher image quality has been achieved due to the miniaturization of ink droplets and the improvement of the color gamut associated with the introduction of multicolor inks. On the other hand, however, demands for color materials and inks are increasing, and more stringent characteristics are required in terms of reliability such as improvement in color development, fixation, and ejection stability.

  On the other hand, the problem of the ink jet recording method when compared with a silver salt photograph is the image storability of the obtained recorded matter. The recorded matter obtained by the ink jet recording method has lower image storability compared to silver salt photography, and when the recorded matter is exposed to light, humidity, heat, environmental gases present in the air for a long time. However, there is a problem that the color material on the recorded material is deteriorated and the color tone of the image is likely to change or fading, and many proposals have been made to solve the above problems.

  For example, there is a proposal for improving fastness by using a colorant having an anthrapyridone structure having a specific structure (see, for example, Patent Documents 1 and 2). The fastness of the recorded matter obtained using the ink containing the dye is very excellent.

However, when the ink containing the color material is used as an ink applied to an ink jet recording apparatus, it may be difficult to ensure reliability. In particular, in an ink jet recording method in which thermal energy is applied to ink for ejection, the heat generating part of the recording head (if the heat generating part is in direct contact with the liquid, the heat generating part itself, or at least one layer of protection on the surface of the heat generating part) In the case of a configuration having a layer, a problem such as kogation occurs in the protective layer), and when printing is performed for a long period of time, deterioration (dissolution) of the wetted surface of the heat generating part or disconnection in the wiring that applies voltage to the heat generating part occurs. There was a case where a problem such as to occur occurred.
JP 2002-332419 A JP 2003-192930 A

  The present inventors examined the cause of the phenomenon described above in the ink containing the color material having excellent fastness. As a result, it has been found that the above phenomenon depends on a specific portion in the color material structure and a specific ion in the ink. The specific site is a substituent that easily releases hydrogen ions, for example, a hydroxyl group bonded to a triazine ring, and the specific ion is a hydroxide ion.

  When a coloring material having a substituent that easily releases hydrogen ions in its structure is in an aqueous solution (ink) state, the ink may have a buffer region (a region that maintains a substantially constant hydrogen ion concentration). The ink having the buffer region has an advantage that, for example, the pH can be maintained constant even when left in various environments such as during distribution, so that the decomposition of the coloring material can be suppressed.

  However, as described above, an ink jet recording apparatus having a heat generating portion containing a metal and / or metal oxide, and using ink having a buffer region and performing continuous printing for a long period of time, ejects ink (to the ink). Each time the thermal energy is applied), the metal and / or metal oxide and hydroxide ions contained in the heat generating part wetted surface react, and the heat generating part wetted surface deteriorates (dissolves), There is also a problem that disconnection occurs in the wiring for applying a voltage to the heat generating portion.

  It is considered that the above problem can be solved by lowering the color material concentration in the ink, for example, by making the content of the color material smaller than 3%. However, when the dye concentration in the ink is lowered, a high density recorded matter may not be obtained.

  The present inventors have solved the above-mentioned problems by devising the composition of the ink, for example, by containing a specific compound in the ink, and can make full use of the colorant having a substituent that easily releases hydrogen ions. I found. The present invention has been made based on this finding.

  Therefore, the object of the present invention is to use the ink for ink containing a color material having a buffer region within the ink use range, and even when performing continuous printing for a long period of time, Another object of the present invention is to provide an inkjet ink that can suppress the occurrence of disconnection in a wiring that applies a voltage to a heat generating portion.

  Another object of the present invention is to provide an ink jet recording method, an ink cartridge, a recording unit and an ink jet recording apparatus using the ink jet ink.

The above object is achieved by the present invention described below. That is, the ink-jet ink of the present invention is used in an ink-jet recording apparatus comprising a recording head having a heat generating part wetted surface containing a metal and / or metal oxide, and the colorant content (mass%). ) Is 3% by mass or more based on the total mass of the inkjet ink, the colorant is a compound represented by the following general formula (V) or a salt thereof , and further the following general formula (I) ) And / or a compound represented by the following general formula (II).

  Formula (I)

In (formula _(I), the R _1, R 2, _{R 3} and _{R 4} each independently, be branched is also an alkyl group having 1 to 6 carbon atoms, _{A 1} O and _{A 2} O is Each independently represents an ethylene oxide group, a propylene oxide group, or a copolymer structure of an ethylene oxide group and a propylene oxide group, and m and n are each independently an integer greater than 0.)
Formula (II)

(In general formula (II), R ₅ is a hydroxyl group or an optionally branched alkyl group having 4 or more carbon atoms, and p is an integer of 4 or more.)

  In addition, an ink jet recording method according to another embodiment of the present invention is characterized in that the ink is an ink jet ink having the above-described configuration in the ink jet recording method including a step of discharging ink by the ink jet method.

  An ink cartridge according to another embodiment of the present invention is an ink cartridge provided with an ink containing portion for containing ink, wherein the ink is an ink jet ink having the above-described configuration.

  According to another embodiment of the present invention, there is provided a recording unit comprising an ink storage portion for storing ink and a recording head for discharging ink, wherein the ink is an inkjet ink having the above-described configuration. It is characterized by being.

  An ink jet recording apparatus according to another embodiment of the present invention is an ink jet recording apparatus having an ink containing portion for containing ink and a recording head for ejecting ink. Ink for use.

  According to the present invention, even when an inkjet ink containing a colorant having a buffer region within the ink use range is used and continuous printing is performed for a long period of time, the heat generation part wetted surface is deteriorated (dissolved) and heat is generated. It is possible to provide an ink jet ink that can suppress the occurrence of disconnection in a wiring that applies a voltage to the portion.

  According to another embodiment of the present invention, an ink jet recording method, an ink cartridge, a recording unit, and an ink jet recording apparatus using the ink jet ink can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  In the present invention, when the color material is a salt, the salt is dissociated into ions in the ink, but it is expressed as “contains a salt” for convenience.

  When the ink of the present invention is used as an inkjet ink, there are many factors that cause the pH of the ink to change. In the present invention, “having a buffer region within the ink use range” means that the ink is in use. It means that the pH of the ink is in the range of the buffer region of the coloring material contained in the ink. Specifically, the factors that cause the pH to change include, for example, storage for a certain period under various environments, evaporation of volatile substances from the ink stored in the ink cartridge, etc. Is mentioned.

  In addition, the deterioration (dissolution) of the liquid contact surface of the heat generating part and the occurrence of disconnection in the wiring for applying a voltage to the heat generating part are caused by the content (mass%) of the color material having a buffer region within the ink use range. This is a phenomenon found when long-term continuous printing is performed using an ink that is 3% by mass or more based on the total mass of the ink.

<Ink>
(Compound represented by general formula (I) / compound represented by general formula (II))
In the present invention, a color material having a buffer region within the ink use range and a compound represented by the following general formula (I) and / or a compound represented by the following general formula (II) are combined for inkjet use. Include in ink. As a result, the compound represented by the general formula (I) and / or the compound represented by the general formula (II) is preferentially adsorbed on the liquid contact surface of the heat generating portion, whereby a hydroxide in the ink is obtained. It is possible to inhibit the adsorption of ions to the liquid contact surface of the heat generating part, and to suppress the deterioration (dissolution) of the liquid surface of the heat generating part and the occurrence of disconnection in the wiring for applying a voltage to the heat generating part.

[Compound represented by formula (I)]
Formula (I)

In (formula _(I), the R _1, R 2, _{R 3} and _{R 4} each independently, be branched is also an alkyl group having 1 to 6 carbon atoms, _{A 1} O and _{A 2} O is Each independently represents an ethylene oxide group, a propylene oxide group, or a copolymer structure of an ethylene oxide group and a propylene oxide group, and m and n are each independently an integer greater than 0.)

  In the present invention, in the general formula (I), 3 ≦ n + m ≦ 30, and the content (mass%) of the general formula (I) is 0.25 mass% or more with respect to the total mass of the ink. It is preferable that it is 5.0 mass% or less. When n + m <3, the solubility of the compound represented by formula (I) in the ink tends to be insufficient and may not be dissolved. On the other hand, if n + m> 30, ejection at the print writing portion when recording an image becomes unstable, and a high-quality recorded matter may not be obtained. Further, in the above general formula (I), even if 3 ≦ n + m ≦ 30, if the content (% by mass) of the above general formula (I) is less than 0.25% by mass, the surface tension of the ink is high. Ink cartridges having a function of generating negative pressure may be difficult to fill with ink, and if the content is more than 5.0% by mass, a print writing unit for recording an image In some cases, the discharge of the ink becomes unstable and a high-quality recorded matter cannot be obtained.

  In particular, in the present invention, in the general formula (I), 5 ≦ n + m ≦ 15, and the content (% by mass) of the general formula (I) is 1.0 mass relative to the total mass of the ink. % To 3.0% by mass is more preferable. By adopting the above-described configuration, it is possible to suppress the deterioration (dissolution) of the wetted surface of the heat generating portion and the occurrence of disconnection in the wiring that applies a voltage to the heat generating portion, and in addition, the discharge at the print writing portion when recording an image. It becomes stable and a higher quality recorded matter can be obtained.

[Compound represented by formula (II)]
Formula (II)

(In general formula (II), R ₅ is a hydroxyl group or an optionally branched alkyl group having 4 or more carbon atoms, and p is an integer of 4 or more.)

  In the present invention, in the general formula (II), 4 ≦ p ≦ 38, and the content (% by mass) of the compound represented by the general formula (II) is 3 with respect to the total mass of the ink. It is preferable that it is 0.0 mass% or more and 10.0 mass% or less. When p <4, the deterioration (dissolution) of the wetted part contact surface can be suppressed to some extent, but the deterioration (dissolution) is likely to proceed, and it does not occur until the disconnection in the wiring for applying a voltage to the heat generating part. In some cases, a printing twist, which is a phenomenon in the previous stage, may occur. If p> 38, ejection failure may occur. In addition, even if 4 ≦ n + m ≦ 38 in the general formula (II), the content (% by mass) of the compound represented by the general formula (II) is less than 3.0% by mass. The effects of the invention may not be sufficiently obtained, and if the content (% by mass) of the compound represented by the general formula (II) is more than 10.0% by mass, the viscosity of the ink increases. This is because, when used as an inkjet ink, reliability such as ejection properties may not be sufficiently secured.

  Moreover, the compound represented by the said general formula (I) and the compound represented by the said general formula (II) can be used in combination. The preferable range of the content in the ink in this case is the same as the case where the compound represented by the above general formula (I) and the compound represented by the above general formula (II) are used alone. Further, the ratio of the content of the compound represented by the general formula (I) and the compound represented by the general formula (II) is not particularly limited, and can be used in an arbitrary range.

(Deterioration of the wetted surface of the heat generating part and the mechanism that causes disconnection in the wiring that applies voltage to the heat generating part)
Here, inkjet ink containing a color material having a buffer region within the ink use range (hereinafter, also simply referred to as “ink”) may cause deterioration (dissolution) of the heat generating part wetted surface or heat generating part. Although the mechanism for generating the disconnection in the wiring to which the voltage is applied is not clear in detail, the present inventors presume as follows.

  When using an ink containing a coloring material that does not have a buffer region within the ink use range, the amount of hydroxide ions present in the ink is small, and the heat generating part contact containing metal and / or metal oxide is present. The amount of hydroxide ions adsorbed on the liquid surface is small. For this reason, when ink is ejected, that is, when a voltage is applied to the heat generating portion and the heat generating portion is heated, the hydroxide ions and the surface contacting the heat generating portion hardly react. As a result, deterioration (dissolution) of the liquid surface of the heat generating part and disconnection in the wiring for applying a voltage to the heat generating part hardly occur.

  On the other hand, when using an ink containing a colorant having a buffer region within the ink use range, the amount of hydroxide ions present in the ink is a color that does not have a buffer region within the ink use range. The amount of hydroxide ions adsorbed on the liquid contact surface of the heat generating portion containing metal and / or metal oxide is also large as compared with the ink containing the material. For this reason, when ink is discharged, that is, when a voltage is applied to the heat generating part and the heat generating part is heated, the hydroxide ions adsorbed on the heat generating part liquid contact surface and the heat generating part liquid contact surface cause a reaction. The liquid contact surface of the heat generating part is dissolved. As a result, the hydroxide ion concentration of the ink decreases in the vicinity of the heat-generating part wetted surface. Here, since the color material in the ink is a color material having a buffer region within the ink use range, it is desired to maintain a substantially constant hydroxide ion concentration against changes in the hydroxide ion concentration of the ink. As a result, the hydroxide ion concentration of the ink increases. The resulting hydroxide ions are adsorbed on the wetted surface of the heat generating part in the same manner as described above. Then, the same phenomenon as described above occurs, and when the ink is discharged, that is, when a voltage is applied to the heat generating part and the heat generating part is heated, the hydroxide ions adsorbed on the liquid contact surface of the heat generating part, and the heat generating part The liquid contact surface causes a reaction, and the heat generation portion liquid contact surface further dissolves.

  The above-described reaction is repeated each time ink is discharged, that is, a voltage is applied to the heat generating portion and the heat generating portion is heated. Therefore, when an ink containing a colorant having a buffer region within the ink use range is used in an ink jet recording apparatus including a recording head having a heat generating part wetted surface containing a metal and / or metal oxide, Deterioration (dissolution) of the heat generating part wetted surface and disconnection in wiring for applying a voltage to the heat generating part occur.

(Color material)
Colorant of the ink according to the present invention is preferably a compound or a salt thereof represented by a general formula (V). The compound or a salt thereof represented by a general formula (V) may be used alone, or may be used in combination.

  In the ink according to the present invention, it is essential that the content (% by mass) of the coloring material is 3% by mass or more with respect to the total mass of the inkjet ink. In addition, the upper limit of the content (% by mass) of the color material is preferably 10.0% by mass or less with respect to the total mass of the ink. When the content exceeds 10.0% by mass, good ink jet characteristics such as fixing recovery properties (capability of recovering by recovery operation such as suction when the ink is fixed on the recording head) cannot be obtained. There may not be.

[Compound represented by formula (V) or a salt thereof]
It is more preferable to use a compound represented by the following general formula (V) or a salt thereof for the color material of the ink according to the present invention. This is because the compound represented by the general formula (V) or a salt thereof can improve the image storage stability such as gas resistance.

  General formula (V)

(In the general formula (V), R ₈ is a hydrogen atom, an alkyl group, a hydroxy lower alkyl group, a cyclohexyl group, a mono- or dialkylaminoalkyl group, or a cyano lower alkyl group, and R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a carboxyl group (except when all of R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are hydrogen atoms). ).)

  The following exemplary compounds 5 to 10 are preferred exemplary compounds of the compound represented by the general formula (V) or a salt thereof. Of course, the present invention is not limited to the following compounds.

  Among the above exemplary compounds, it is particularly preferable to use the following exemplary compound A, which is the sodium salt of exemplary compound 10.

  Exemplary Compound A

[Color material verification method]
For the verification of the color material used in the present invention, the following verification methods (1) to (3) using high performance liquid chromatography (HPLC) can be applied.
(1) Peak retention time (2) Maximum absorption wavelength at peak of (1) (3) M / Z of mass spectrum at peak of (1) (posi, negative)

The analysis conditions of high performance liquid chromatography are as follows. An ink solution diluted about 1000 times with pure water is analyzed by high performance liquid chromatography under the following conditions, and a peak retention time and a maximum absorption wavelength of the peak are measured.
Column: Symmetry C18 2.1mm x 150mm
-Column temperature: 40 ° C
・ Flow rate: 0.2 ml / min
PDA: 210 nm to 700 nm
Mobile phase and gradient conditions: Table 1

The analysis conditions of the mass spectrum are as shown below. With respect to the obtained peak, a mass spectrum is measured under the following conditions, and the most strongly detected M / Z is measured for each of posi and negative.
・ Ionization method ・ ESI capillary voltage 3.5kV
Desolvent gas 300 ℃
Ion source temperature 120 ° C
・ Detector posi 40V 200-1500amu / 0.9sec
nega 40V 200-1500amu / 0.9sec
Table 2 shows the retention time, maximum absorption wavelength, M / Z (posi), and M / Z (negative) values for Example Compound A. When it corresponds to the value shown in Table 2, it can be judged that it corresponds to the compound used in the present invention.

(Buffer area)
The buffer region in the present invention is a pH region where the solution maintains a substantially constant hydrogen ion concentration despite the addition or disappearance of a certain amount of acid or base. The titration of FIG. 1 shows the results of measuring the change in pH of the solution by adding acid or base to the solution, taking the amount of acid or base added on the horizontal axis, and the pH of the solution on the vertical axis. It is a curve. In FIG. 1, the buffer region is a region before and after a region where the pH change is small (with two inflection points of the titration curve as a boundary). For example, the buffer region of Exemplified Compound 2 ranges from A to B in FIG.

  In the present invention, “having a buffer region within the ink use range” means that the ink itself and the color material itself change during use of the ink as well as the initial pH after ink preparation. Therefore, the ink pH is also included in the buffer area afterward.

  FIG. 1 is an acid-base titration curve of Exemplified Compound A and Exemplified Compound 2. In FIG. 1, the vertical axis represents the pH of the color material aqueous solution, and the horizontal axis represents the amount of acid or base added. On the horizontal axis, a number greater than 0 is the amount of sodium hydroxide aqueous solution added as a base, and a number smaller than 0 is the amount of nitric acid aqueous solution added as an acid.

  A specific example of the procedure for obtaining the titration curve of the color material aqueous solution is as follows. Prepare 2 liters of a 10% by weight aqueous solution of the color material and measure the initial pH. And the pH of the 10 mass% aqueous solution of the said color material is adjusted to 7.0 using an acid or a base. The 10% by mass aqueous solution of the color material having the pH adjusted to 7 obtained above is divided into two equal portions of about 1 liter. The acid was added to 1 liter of the 10% by weight aqueous solution of the color material adjusted to pH 7.0, which was obtained above, and the pH of the other one obtained above was adjusted to 7. A base is added to a 10% by mass aqueous solution of the coloring material, and the pH of the aqueous coloring material solution is measured.

  The titration curves of Exemplified Compound A and Exemplified Compound 2 determined by the above method are shown in FIG. As can be seen from FIG. 1, the buffer region of Exemplified Compound A has a pH of 6.5 to 11.8, and the buffer region of Exemplified Compound 2 has a pH of 7.3 to 10.5.

(Aqueous medium)
The ink composition of the present invention can use water or an aqueous medium that is a mixed solvent of water and various water-soluble organic solvents.

  The water-soluble organic solvent is not particularly limited as long as it is water-soluble, and alcohol, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. Specifically, for example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol; dimethylformamide, Amides such as dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyhydric alcohols such as trimethylolpropane and trimethylolethane can be used. Of course, the present invention is not limited to these. The water-soluble organic solvent may be used alone or as a mixture.

  The content of these water-soluble organic solvents is preferably 5% by mass to 90% by mass and more preferably 10% by mass to 50% by mass with respect to the total mass of the ink. When the content is less than this range, when used as an inkjet ink, there is a possibility that the reliability such as ejection properties may deteriorate. When the content is more than this range, the ink viscosity increases. This is because a supply failure may occur.

  Moreover, it is preferable to use deionized water (ion exchange water) as the water. The water content is preferably 10% by mass to 90% by mass with respect to the total mass of the ink.

(Other additives)
Furthermore, in the present invention, a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, an evaporation accelerator, a chelating agent, and a water-solubility, if necessary. Various additives such as a polymer may be contained.

<Recording medium>
As the recording medium used when forming an image using the ink of the present invention, any recording medium can be used as long as recording is performed by applying ink.

  The present invention is applied to a recording medium in which a color material such as a color material or a pigment is adsorbed to fine particles forming a porous structure in an ink receiving layer and an image is formed from at least the adsorbed fine particles. It is particularly suitable for use. Such an ink jet recording medium is preferably of a so-called absorption type in which ink is absorbed by a gap formed in an ink receiving layer on a support.

  The absorption type ink-receiving layer is constituted as a porous layer mainly composed of fine particles and containing a binder and other additives as required. Specific examples of the fine particles include inorganic pigments such as silica, clay, talc, calcium carbonate, kaolin, alumina or alumina hydrate, diatomaceous earth, titanium oxide, hydrotalcite, zinc oxide, urea formalin resin, ethylene resin. And organic pigments such as styrene resins, and one or more of these are used. Examples of suitable binders include water-soluble polymers and latex. For example, polyvinyl alcohol or a modified product thereof, starch or a modified product thereof, gelatin or a modified product thereof, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, hydroxyprooylmethylcellulose and other cellulose derivatives, SBR latex, NBR latex, methylmethacrylate-butadiene Polymer latex, functional group-modified polymer latex, vinyl copolymer latex such as ethylene vinyl acetate copolymer, polyvinyl pyrrolidone, maleic anhydride or copolymer thereof, acrylate copolymer, etc. are used and necessary Depending on the situation, two or more kinds can be used in combination. In addition, additives can also be used. For example, a dispersant, a thickener, a pH adjuster, a lubricant, a fluidity modifier, a surfactant, an antifoaming agent, a mold release agent, a fluorescence enhancer, if necessary. Whitening agents, ultraviolet absorbers, antioxidants and the like are used.

In particular, the recording medium preferably used in the present invention is preferably a recording medium mainly composed of fine particles having an average particle diameter of 1 μm or less and having an ink receiving layer formed thereon. Particularly preferable examples of the fine particles include silica fine particles and aluminum oxide fine particles. A preferable silica fine particle is a silica fine particle typified by colloidal silica. Colloidal silica itself can be obtained from the market, and in particular, those described in, for example, Japanese Patent Nos. 2803134 and 2881847 are preferable. Preferred as the aluminum oxide fine particles are alumina hydrate fine particles and the like. One example of such alumina hydrate fine particles is an alumina hydrate represented by the following general formula.
AlO _3-n (OH) _2n · mH ₂ O
(In the above formula, n represents an integer of 1, 2 or 3, and m represents a value of 0 to 10, preferably 0 to 5. However, m and n are not 0 at the same time. MH _{Since 2} O often also represents a detachable aqueous phase that is not involved in the formation of the mH ₂ O crystal lattice, m can take an integer or non-integer value. M can reach a value of 0 when heated.)

  Alumina hydrate is obtained by hydrolysis of aluminum alkoxide, hydrolysis of sodium aluminate described in US Pat. No. 4,242,271 and US Pat. No. 4,202,870, or Japanese Patent Publication No. 57-44605. Can be produced by a known method such as a method of neutralizing by adding an aqueous solution of sodium sulfate, aluminum chloride or the like to an aqueous solution of sodium aluminate or the like described in 1.

  The recording medium preferably has a support for supporting the ink receiving layer. The support is not particularly limited as long as the ink receiving layer can be formed of the above-described porous fine particles and gives rigidity that can be transported by a transport mechanism such as an ink jet printer. Even things can be used. Specifically, for example, a paper support made mainly of natural cellulose fibers and made of pulp raw materials, a plastic support made of a material such as polyester (eg, polyethylene terephthalate), cellulose triacetate, polycarbonate, polyvinyl chloride, polypropylene, polyimide, etc. And a resin-coated paper (eg, RC paper) having a polyolefin resin-coated layer in which a white pigment or the like is added to at least one of the base papers.

<Ink set>
The ink of the present invention can be preferably used even when an ink set is combined with other inks. The ink set in the present invention is a state in which the ink of the present invention is used together with other inks such as cyan ink, magenta ink, yellow ink, and black ink. There is no particular limitation on other inks that can be combined as an ink set. In addition, the ink set in the present invention includes a case where a plurality of ink tanks are integrated, and includes a case where a plurality of individual ink tanks are used in combination. One thing is also included.

<Inkjet recording method>
The ink according to the present invention is particularly preferably used in an ink jet recording method having a step of ejecting ink by an ink jet method. Ink jet recording methods include a recording method in which mechanical energy is applied to ink and ink is ejected, and a recording method in which thermal energy is applied to ink and ink is ejected. In particular, in the present invention, an ink jet recording method using thermal energy can be preferably used.

<Ink cartridge>
Examples of the ink cartridge suitable for performing recording using the ink according to the present invention include an ink cartridge including an ink storage portion for storing these inks.

<Recording unit>
A recording unit suitable for performing recording using the ink according to the present invention includes a recording unit including an ink storage unit for storing these inks and a recording head. In particular, there is a recording unit in which the recording head causes thermal energy corresponding to a recording signal to act on the ink and generates ink droplets by the energy.

  The recording head in the present invention has a heat generating part liquid contact surface containing a metal and / or a metal oxide. Specific examples of the metal and / or metal oxide include metals such as Ta, Zr, Ti, and NiAl, and oxides of these metals.

<Inkjet recording apparatus>
A recording apparatus suitable for performing recording using the ink according to the present invention applies thermal energy corresponding to a recording signal to ink in a recording head having an ink storage unit in which these inks are stored. An apparatus that generates ink droplets by energy is used.

  Below, the schematic structure of the mechanism part of an inkjet recording device is demonstrated. The recording apparatus main body is composed of a paper feed unit, a paper transport unit, a carriage unit, a paper discharge unit, a cleaning unit, and an exterior unit that protects these parts and has design properties from the role of each mechanism. The outline of these will be described below.

  FIG. 2 is a perspective view of the recording apparatus. 3 and 4 are diagrams for explaining the internal mechanism of the recording apparatus main body. FIG. 3 is a perspective view from the upper right part, and FIG. 4 is a side sectional view of the recording apparatus main body. is there.

  When paper feeding is performed in the recording apparatus, first, only a predetermined number of recording media are sent to a nip portion including a paper feed roller M2080 and a separation roller M2041 in a paper feed unit including a paper feed tray M2060. The sent recording medium is separated at the nip portion, and only the uppermost recording medium is conveyed. The recording medium sent to the paper transport unit is guided by the pinch roller holder M3000 and the paper guide flapper M3030, and is sent to the roller pair of the transport roller M3060 and the pinch roller M3070. A roller pair composed of a conveyance roller M3060 and a pinch roller M3070 is rotated by driving of the LF motor E0002, and the recording medium is conveyed on the platen M3040 by this rotation.

  When an image is formed on the recording medium in the carriage unit, the recording head H1001 (FIG. 5) is disposed at a target image forming position, and ink is ejected onto the recording medium in accordance with a signal from the electric substrate E0014. Although the detailed configuration of the recording head H1001 will be described later, a recording main scan in which the carriage M4000 scans in the column direction while recording by the recording head H1001, and a sub-scan in which the recording medium is conveyed in the row direction by the conveyance roller M3060. By alternately repeating the above, an image is formed on the recording medium.

  The recording medium on which the image is finally formed is sandwiched by the nip between the first paper discharge roller M3110 and the spur M3120 at the paper discharge unit, conveyed, and discharged to the paper discharge tray M3160.

  For the purpose of cleaning the recording head H1001 before and after image recording in the cleaning unit, if the pump M5000 is operated in a state where the cap M5010 is in close contact with the ink discharge port of the recording head H1001, it is unnecessary from the recording head H1001. Ink or the like is sucked. Further, by sucking the ink remaining in the cap M5010 with the cap M5010 opened, consideration is given to preventing the remaining ink from adhering and the subsequent adverse effects.

(Recording head configuration)
The configuration of the head cartridge H1000 will be described. The head cartridge H1000 has a recording head H1001, means for mounting the ink tank H1900, and means for supplying ink from the ink tank H1900 to the recording head, and is detachably mounted on the carriage M4000. .

  FIG. 5 is a diagram showing how the ink tank H1900 is mounted on the head cartridge H1000. The recording apparatus forms an image with yellow, magenta, cyan, black, light magenta, light cyan, and green ink, and therefore, ink tank H1900 is also prepared for seven colors independently. In the above, the ink according to the present invention is used as at least one kind of ink. As shown in the figure, each is detachable from the head cartridge H1000. The ink tank H1900 can be attached and detached while the head cartridge H1000 is mounted on the carriage M4000.

  FIG. 6 is an exploded perspective view of the head cartridge H1000. In the figure, a head cartridge H1000 includes a first recording element substrate H1100 and a second recording element substrate H1101, a first plate H1200, a second plate H1400, an electric wiring substrate H1300, a tank holder H1500, and a flow path forming member H1600. , Filter H1700, seal rubber H1800, and the like.

  The first recording element substrate H1100 and the second recording element substrate H1101 are Si substrates, and a plurality of recording elements (nozzles) for ejecting ink are formed on one side thereof by a photolithography technique. Electric wiring such as Al for supplying electric power to each recording element is formed by a film forming technique, and a plurality of ink flow paths corresponding to individual recording elements are also formed by a photolithography technique. Further, an ink supply port for supplying ink to the plurality of ink flow paths is formed to open on the back surface.

  FIG. 7 is an enlarged front view for explaining the configuration of the first recording element substrate H1100 and the second recording element substrate H1101. H2000 to H2600 are printing element rows (hereinafter also referred to as nozzle rows) corresponding to different ink colors, and the first printing element substrate H1100 has a nozzle row H2000 supplied with yellow ink and a supply of magenta ink. The nozzle row for three colors is configured, that is, the nozzle row H2100 to be supplied and the nozzle row H2200 to which cyan ink is supplied. The second recording element substrate H1101 includes a nozzle row H2300 supplied with light cyan ink, a nozzle row H2400 supplied with black ink, a nozzle row H2500 supplied with orange ink, and a nozzle supplied with light magenta ink. Nozzle rows for four colors of the row H2600 are configured.

Each nozzle row is composed of 768 nozzles arranged at an interval of 1200 dpi (dot / inch; reference value) in the conveyance direction of the recording medium, and ejects approximately 2 picoliters of ink droplets. The opening area at each nozzle outlet is set to approximately 100 square μm ² . Further, the first recording element substrate H1100 and the second recording element substrate H1101 are bonded and fixed to the first plate H1200. Here, the first recording element substrate H1100 and the second recording element substrate H1101 are attached. An ink supply port H1201 for supplying ink is formed.

  Further, a second plate H1400 having an opening is bonded and fixed to the first plate H1200. The second plate H1400 is composed of an electric wiring substrate H1300, a first recording element substrate H1100, and a second recording element substrate H1100. The electric wiring substrate H1300 is held so that the recording element substrate H1101 is electrically connected.

  The electrical wiring substrate H1300 applies an electrical signal for ejecting ink from each nozzle formed on the first recording element substrate H1100 and the second recording element substrate H1101, and the first recording element substrate Electrical wiring corresponding to the H1100 and the second recording element substrate H1101, and an external signal input terminal H1301 for receiving an electrical signal from the recording apparatus main body located at the end of the electrical wiring. The external signal input terminal H1301 is positioned and fixed on the back side of the tank holder H1500.

  On the other hand, in a tank holder H1500 that holds the ink tank H1900, a flow path forming member H1600 is fixed by, for example, ultrasonic welding to form an ink flow path H1501 that communicates from the ink tank H1900 to the first plate H1200.

  A filter H1700 is provided at the ink tank side end of the ink flow path H1501 that engages with the ink tank H1900, and can prevent dust from entering from the outside. Further, a seal rubber H1800 is attached to the engaging portion with the ink tank H1900 so that ink can be prevented from evaporating from the engaging portion.

  Further, as described above, the tank holder portion composed of the tank holder H1500, the flow path forming member H1600, the filter H1700, and the seal rubber H1800, the first recording element substrate H1100, the second recording element substrate H1101, and the first plate. The head cartridge H1000 is configured by bonding the recording head unit H1001 including the H1200, the electric wiring substrate H1300, and the second plate H1400 by bonding or the like.

  Here, as an embodiment of the recording head, a bubble jet (registration) that performs recording using an electrothermal transducer (recording element) that generates thermal energy for causing film boiling to the ink in response to an electrical signal. A trademark type recording head has been described with an example.

  About this typical structure and principle, for example, what is performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 is preferable. . This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it corresponds to a sheet or liquid flow path in which liquid (ink) is held. By applying at least one drive signal that corresponds to the recorded information and gives a rapid temperature rise exceeding the nucleate boiling to the electrothermal transducer arranged in a manner, heat energy is generated in the electrothermal transducer, This is effective because film boiling occurs on the heat acting surface of the recording head, and as a result, bubbles in the liquid (ink) corresponding to the drive signal on a one-to-one basis can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape because bubbles can be grown and contracted immediately and appropriately, and liquid (ink) discharge with particularly excellent responsiveness can be achieved.

  Further, as a form of the ink jet recording apparatus using the second mechanical energy, a nozzle forming substrate having a plurality of nozzles, a pressure generating element made of a piezoelectric material and a conductive material disposed opposite to the nozzles, and this pressure An on-demand ink jet recording head that includes ink that fills the periphery of the generating element, displaces the pressure generating element by an applied voltage, and discharges a small droplet of ink from a nozzle can be exemplified.

  Further, the ink jet recording apparatus is not limited to the one in which the head and the ink tank are separated as described above, and may be one in which they are integrated so as not to be separated. The ink tank is integrated with the head in a separable or non-separable manner and mounted on the carriage, and is provided at a fixed portion of the apparatus to supply ink to the recording head via an ink supply member, for example, a tube. It may be in the form of Further, when the ink tank is provided with a configuration for applying a preferable negative pressure to the recording head, a configuration in which an absorber is disposed in the ink storage portion of the ink tank, or a flexible ink storage bag and the same A form having a spring portion that applies a biasing force in the direction of expanding the internal volume can be employed. In addition to the serial recording method as described above, the recording apparatus may take the form of a line printer in which recording elements are aligned over a range corresponding to the entire width of the recording medium.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example and a reference example, this invention is not limited at all by the following Example, unless the summary is exceeded. Unless otherwise specified, the ink components in Examples and Comparative Examples mean “parts by mass”.

<Compound represented by formula (I)>
Commercially available compounds were used as the compound represented by the general formula (I) and the comparative compound. Table 3 below shows specific structures of the compound represented by formula (I) and the comparative compound used in Examples and Comparative Examples. Of course, the present invention is not limited to the compounds shown in Table 3. In addition, the compound represented by general formula (I) analyzed by the gel permeation chromatography made from Waters, and calculated | required the value of n + m. The analysis conditions of gel permeation chromatography are as follows.
Column: Shodex (Showa Denko)
-Mobile phase: Tetrahydrofuran-Flow rate: 1 mL / min

(Compound represented by formula (II) )
A commercially available compound was used as the compound represented by the general formula (II). Table 4 below shows specific structures of the compounds represented by the general formula (II) used in Examples and Comparative Examples. Of course, the present invention is not limited to the compounds shown in Table 4. In addition, the compound represented by general formula (II) analyzed using gel permeation chromatography, and calculated | required the value of p. The analysis conditions for gel permeation chromatography are the same as described above.

<Compound represented by formula (III) or salt thereof>
The coloring material having the structure of the exemplary compound 2 was synthesized according to the method described in European Patent Publication EP-682 088 A1.

<Preparation of coloring material which is compound represented by general formula (V)>
In xylene, the compound represented by the following compound (1), sodium carbonate, and ethyl benzoyl acetate were reacted, and the reaction product was filtered and washed. This was reacted in N, N-dimethylformamide by sequentially adding metaaminoacetanilide, copper acetate, and sodium carbonate, and the reaction product was filtered and washed. Further, after sulfonation in fuming sulfuric acid, filtration and washing were performed, and this was subjected to a condensation reaction with cyanuric chloride in the presence of sodium hydroxide. Anthranilic acid was added to the reaction solution, and a condensation reaction was performed in the presence of sodium hydroxide. This was filtered and washed to obtain the following exemplary compound A.

  Compound (1)

  Exemplary Compound A

<Preparation of ink>
After mixing each component shown in Table 5 and Table 6 and stirring sufficiently, pressure filtration was performed with a filter having a pore size of 0.2 μm to prepare inks of Examples 1 to 20 and Comparative Examples 1 to 3. .

  In all of the inks of Examples and Comparative Examples, it was confirmed by measuring the pH of the ink that the pH of the ink was in the buffer region. Whereas the buffer region of Exemplified Compound A has a pH of 6.5 or more and 11.8 or less, the pHs of the inks of Examples 1 to 8, 10 to 15, and 17 to 20 and Comparative Examples 1 and 2 are It was within this range. Further, the buffer region of Exemplified Compound 2 has a pH of 7.3 or more and 10.5 or less, whereas the pHs of the inks of Examples 9 and 17 and Comparative Example 3 were within this range.

<Evaluation of printing durability>
The ink obtained above is filled with magenta ink using an ink jet recording apparatus (trade name: BJ F890; manufactured by Canon) that applies thermal energy to the ink and ejects ink droplets. Then, a printing durability test was performed using a pattern printed on an A4 size recording medium with 100% duty. The criteria for evaluation are as follows. Tables 5 and 6 show the evaluation results of the printing durability.
AA: No trouble occurs even when printing 20000 sheets.
A: When printing 15000 to 19999 sheets, slight blurring due to minute twist occurs.
B: When 10000 to 14999 sheets are printed, slight blurring due to minute twist occurs.
C: Before printing 10000 sheets, blurring occurs or non-ejection due to disconnection occurs.
AA and A were judged to be acceptable levels, B was judged to be an acceptable level without problems in actual use, and C was judged to be an unacceptable level.

  As can be seen from Comparative Example 1, when the ink contains a compound represented by the general formula (I) and / or a compound different from the compound represented by the general formula (II), disconnection occurs, resulting in failure. Discharge occurs. Further, as can be seen from Comparative Example 2, when the ink does not contain the compound represented by the general formula (I) and / or the compound represented by the general formula (II), disconnection occurs, resulting in non-ejection. Occurs. Further, as can be seen from Example 2, when the ink contains the compound represented by the general formula (I), it is possible to suppress deterioration of the liquid contact surface of the heat generating portion and occurrence of disconnection, and non-ejection. Does not occur. Further, as can be seen from Example 4, when the ink contains a compound represented by the general formula (III) or a salt thereof and a compound represented by the general formula (I), deterioration of the wetted surface of the heat generating part In addition, occurrence of disconnection can be suppressed, non-ejection does not occur, and high-quality recorded matter can be obtained. Further, as can be seen from Examples 1 to 8, when the ink contains the compound represented by the general formula (V) or a salt thereof, and the compound represented by the general formula (I), the heating portion wetted surface Deterioration and disconnection can be suppressed, non-ejection does not occur, and high-quality recorded matter can be obtained.

  As can be seen from Examples 1, 2, and 3 to 5, the ink contains a compound represented by the general formula (I), and in the general formula (I), 3 ≦ n + m ≦ 30, and When the content of the compound represented by the general formula (I) is 0.25% by mass or more and 5.0% by mass or less with respect to the total mass of the ink (Examples 3 to 5), the ink has the general formula ( Compared with the case where the compound represented by I) is contained and further deviates from the above range (Examples 1 and 2), it is possible to more effectively suppress the deterioration of the wetted part liquid contact surface and the occurrence of disconnection. Further, as can be seen from Examples 3 and 4, the ink contains a compound represented by the general formula (I), and in the general formula (I), 5 ≦ n + m ≦ 15, and the general formula When content of the compound represented by (I) is 1.0 mass% or more and 3.0 mass% or less, the effect in this invention can be acquired most effectively.

As can be seen from Comparative Example 3, when the ink does not contain the compound represented by the general formula (I) and / or the compound represented by the general formula (II), disconnection occurs, resulting in non-ejection. . Further, as can be seen from Reference Example 2 , when the ink contains the compound represented by the general formula (II), it is possible to suppress deterioration of the liquid contact surface of the heat generating portion and occurrence of disconnection, and non-ejection. Does not occur. Further, as can be seen from Examples 10 to 13, 14, and 16, the ink contains a compound represented by the general formula (II), and in the general formula (II), 8 ≦ p ≦ 38, When the content of the compound represented by the general formula (II) is 3.0% by mass or more and 10.0% by mass or less with respect to the total mass of the ink (Examples 10 to 13), Compared with the case where the compound represented by the formula (II) is contained and further deviates from the above range (Examples 14 and 16), it is possible to more effectively suppress the degradation of the heat generating part wetted surface and the occurrence of disconnection. . Further, as can be seen from Example 19, when the ink contains a compound represented by the general formula (II) in which R ₅ is an alkyl group having 16 carbon atoms, The occurrence of disconnection can be suppressed, and no non-ejection occurs. Further, as can be seen from Example 20, when the ink is used in combination with the compound represented by the general formula (I) and the compound represented by the general formula (II), the deterioration of the wetted surface of the heat generating part In addition, the occurrence of disconnection can be suppressed, and no non-ejection occurs.

In the evaluation results of the printing durability, Comparative Example 2 and Example 4 are C and AA, and Comparative Example 3 and Reference Example 1 are B and AA. Similarly, in Comparative Example 2 and Example 10, C and AA, and in Comparative Example 3 and Example 17, B and AA. From this, the compound represented by the general formula (I) and / or the compound represented by the general formula (II) is used in combination with the exemplified compound A rather than the exemplified compound 2, and the heat generating part wetted surface It can be seen that the effect of suppressing the deterioration and disconnection is great. In the evaluation results of printing durability, C and AA are shown in Comparative Example 2 and Example 4, and B and AA are shown in Comparative Example 3 and Reference Example 1 . Similarly, in Comparative Example 2 and Example 10, C and AA, and in Comparative Example 3 and Example 17, B and AA. Therefore, the compound represented by the general formula (I) and / or the compound represented by the general formula (II) is used in combination with the exemplified compound A rather than the exemplified compound 2, and is in contact with the heat generating part. It can be seen that the effect of suppressing surface degradation and disconnection is great.

2 is a titration curve of Exemplified Compound A and Exemplified Compound 2. 1 is a perspective view of a recording apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of a mechanism unit of the recording apparatus according to the embodiment of the invention. 1 is a cross-sectional view of a recording apparatus in an embodiment of the present invention. FIG. 5 is a perspective view showing a state where an ink tank is mounted on the head cartridge applied in the embodiment of the present invention. It is a disassembled perspective view of the head cartridge applied in the embodiment of the present invention. FIG. 3 is a front view showing a recording element substrate in a head cartridge applied in an embodiment of the present invention.

Explanation of symbols

M2041 Separation roller M2060 Paper feed tray M2080 Paper feed roller M3000 Pinch roller holder M3030 Paper guide flapper M3040 Platen M3060 Transport roller M3070 Pinch roller M3110 Paper discharge roller M3120 Spur M3160 Paper discharge tray M4000F Carriage M5000 Pump M500P Head cartridge H1001 Recording head H1100 First recording element substrate H1101 Second recording element substrate H1200 First plate H1201 Ink supply port H1300 Electrical wiring substrate H1301 External signal input terminal H1400 Second plate H1500 Tank holder H1501 Ink channel H1600 Flow path forming member H1700 Luther H1800 seal rubber H1900 ink tank H2000 yellow nozzle row H2100 magenta nozzle row H2200 cyan nozzle row H2300 light cyan nozzle row H2400 black nozzle row H2500 green nozzle row H2600 light magenta nozzle row

Claims (8)

Used in an ink jet recording apparatus comprising a recording head having a heat generating part wetted surface containing a metal and / or metal oxide, and the content (% by mass) of the color material is based on the total mass of the ink for ink jet In the inkjet ink of 3% by mass or more,
The colorant is a compound represented by the following general formula (V) or a salt thereof, and further a compound represented by the following general formula (I) and / or a compound represented by the following general formula (II): An ink-jet ink comprising the ink-jet ink.
Formula (I)

In (formula _(I), the R _1, R 2, _{R 3} and _{R 4} each independently, be branched is also an alkyl group having 1 to 6 carbon atoms, _{A 1} O and _{A 2} O is Each independently represents an ethylene oxide group, a propylene oxide group, or a copolymer structure of an ethylene oxide group and a propylene oxide group, and m and n are each independently an integer greater than 0.)
Formula (II)

(In general formula (II), R ₅ is a hydroxyl group or an optionally branched alkyl group having 4 or more carbon atoms, and p is an integer of 4 or more.)
General formula (V)

(In the general formula (V), R ₈ is a hydrogen atom, an alkyl group, a hydroxy lower alkyl group, a cyclohexyl group, a mono- or dialkylaminoalkyl group, or a cyano lower alkyl group, and R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or a carboxyl group (except when all of R ₉ , R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are hydrogen atoms). ).) In the above general formula (I), 3 ≦ n + m ≦ 30, and the content (% by mass) of the above general formula (I) is 0.25% by mass or more and 5.0% by mass with respect to the total mass of the ink. The inkjet ink according to claim 1, wherein: In the general formula (II), 4 ≦ p ≦ 38, and the content (% by mass) of the general formula (II) is 3.0% by mass or more and 10.0% by mass with respect to the total mass of the ink. less ink jet ink according to claim 1 or 2. The inkjet recording method which has the process of discharging an ink with an inkjet method, The said ink is the inkjet ink of any one of Claims 1-3 , The inkjet recording method characterized by the above-mentioned. The ink jet recording method according to claim 4 , wherein the ink jet method discharges ink by applying thermal energy to the ink. An ink cartridge comprising an ink container for containing ink, wherein the ink is the ink jet ink according to any one of claims 1 to 3 . A recording unit including an ink storage portion that stores ink and a recording head for ejecting ink, wherein the ink is the ink jet ink according to any one of claims 1 to 3. And recording unit. An ink jet recording apparatus comprising an ink containing portion for containing ink and a recording head for ejecting ink, wherein the ink is the ink for ink jet according to any one of claims 1 to 3. An ink jet recording apparatus.

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